Well, this is certainly a bit of neglecting attitude to give you a rulebook which requires you to have two other rulebooks in order to play properly, is it not?

You mean it should duplicate all 400 pages from the main rules? The Task Force book is an extension of the main rules, it doesn't give any stats or special rules for units. Amazingly it doesn't say so either on the cover or anywhere in the text, nor which additional books you'll need. No wonder customers are confused. Worse, all references to the existing rules are to the Player's Edition only, e.g. "Setting up terrain" which is actually copied from The Deluge and not in the main rulebook(!). They could at least have included references to the older books, even if there have been rules updates in the PE (hopefully available as errata soon).

So, to sum up you either need 2nd Ed rulebook + The Deluge + (non existing) Errata, or 2nd Ed + PE (+ The Deluge if you want to play Imperial/Brandenburg/Transylvanian armies, plus others for Gdansk and Denmark/Norway). Some people claim that the Army Builder makes the printed army lists unnecessary; I believe this to be a false assumption.

Second question, where do you find the rules for thinks like Orthodox Priests and the unit specific rules that are not in the Mini Rule Book?

I believe there are still plans to publish books for each faction in the main rulebook. These should have the different skirmish lists and the unit description, stats and rules. So, everything that's in the main rulebook but not in the players edition.